Allow scroll to clear all in 3 button+fallback mode

We weren't calling onSwipeUpToRecentsComplete(), which meant we kept the
disallowScrollToClearAll from prepareRecentsUi indefinitely.

Also don't update the icon scale if it is supposed to be scaled down, to
avoid it from scaling up and overlapping with the app window.

Fixes: 141184247
Change-Id: I49406764373e7121e289da7477dcbb58d0b98fd5